Catheter sheath introducers are well-known and in clinical use, comprising an intravascular cannula which carries a proximal hub. The hub, in turn, carries a slit elastomer partition valve through which a catheter or a guidewire can penetrate to provide sealing advancement through the cannula of the catheter sheath introducer. Also, it is typical for a branch line to connect with the hub and the interior of the cannula for flushing, and for obtaining blood samples, as the cannula of the catheter sheath introducer occupies a position penetrating through the skin and the wall of an artery to reside in the artery. Thus, catheters can then be advanced and withdrawn through the catheter sheath introducer, while minimizing further injury to the patient above and beyond the single emplacement of the catheter sheath introducer through the skin and artery wall.
Catheter sheath introducers are typically advanced through the skin and an artery wall while a penetrating stylette (also called a "dilator") occupies the lumen of the catheter sheath introducer cannula. The stylette penetrates through the skin and artery wall, taking the catheter sheath introducer with it.
However, difficulties are encountered because the cannula of the catheter sheath introducer naturally has a wall thickness, resulting in a distal end which causes resistance to advancement of the stylette and catheter sheath introducer through the skin and the artery wall.
In accordance with this invention, an intravascular cannula is provided which has a distal tip that greatly reduces resistance of the cannula to advancement through the skin and into an artery while positioned about a stylette. By this, tissue damage and difficulty of emplacement of such an intravascular cannula can be greatly reduced.